Pub Date : 2025-04-14DOI: 10.1016/j.ijpddr.2025.100591
Fernanda G. Fumuso , Jason A. Clement , Matthew J. Todd , Roberta M. O'Connor
Toxoplasmosis is a worldwide parasitic disease caused by the apicomplexan Toxoplasma gondii. Severe neurological illness occurs in immunosuppressed patients, and congenital disorders can follow transplacental primo infection during pregnancy. New effective antiparasitic drugs are needed since chronic cystic stages are resistant to current available treatments, and some of the congenital infections are unresponsive to available therapeutics. Tartrolon E (trtE) is a marine secondary metabolite that has high selectivity against human and animal apicomplexan parasites including T. gondii, Cryptosporidium parvum and Plasmodium falciparum. We evaluated the effect of the compound on extracellular tachyzoite viability, morphology, membrane permeability and its ability to block host cell attachment and/or invasion. While 80 % of T. gondii infective capacity is blocked after only 30 min of compound treatment, parasite viability, morphology, membrane integrity and host cell attachment were unaffected until after 4 h of treatment. These effects were irreversible when parasites were allowed to infect host cells after trtE treatment. Drug exposure for more than 4 h significantly affected tachyzoite survival and altered parasite morphology. The mechanism of action of trtE is still unknown but includes blocking parasite invasion processes. Further research is needed to determine the molecular target of trtE to further progress the compound as an antiparasitic candidate.
{"title":"Tartrolon E rapidly blocks Toxoplasma gondii capacity to invade host cells","authors":"Fernanda G. Fumuso , Jason A. Clement , Matthew J. Todd , Roberta M. O'Connor","doi":"10.1016/j.ijpddr.2025.100591","DOIUrl":"10.1016/j.ijpddr.2025.100591","url":null,"abstract":"<div><div>Toxoplasmosis is a worldwide parasitic disease caused by the apicomplexan <em>Toxoplasma gondii</em>. Severe neurological illness occurs in immunosuppressed patients, and congenital disorders can follow transplacental primo infection during pregnancy. New effective antiparasitic drugs are needed since chronic cystic stages are resistant to current available treatments, and some of the congenital infections are unresponsive to available therapeutics. Tartrolon E (trtE) is a marine secondary metabolite that has high selectivity against human and animal apicomplexan parasites including <em>T. gondii</em>, <em>Cryptosporidium parvum</em> and <em>Plasmodium falciparum</em>. We evaluated the effect of the compound on extracellular tachyzoite viability, morphology, membrane permeability and its ability to block host cell attachment and/or invasion. While 80 % of <em>T. gondii</em> infective capacity is blocked after only 30 min of compound treatment, parasite viability, morphology, membrane integrity and host cell attachment were unaffected until after 4 h of treatment. These effects were irreversible when parasites were allowed to infect host cells after trtE treatment. Drug exposure for more than 4 h significantly affected tachyzoite survival and altered parasite morphology. The mechanism of action of trtE is still unknown but includes blocking parasite invasion processes. Further research is needed to determine the molecular target of trtE to further progress the compound as an antiparasitic candidate.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"28 ","pages":"Article 100591"},"PeriodicalIF":4.1,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143830062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-26DOI: 10.1016/j.ijpddr.2025.100589
Dave Leathwick, Peter Green, Charlotte Bouchet, Alex Chambers, Tania Waghorn, Christian Sauermann
In the faecal egg count reduction test, visual identification of larvae cultured from faeces enables the egg counts to be apportioned to species/genera, resulting in a more accurate test. However, morphology cannot reliably differentiate some species meaning that, in some cases, efficacy can only be estimated at the genus or species-complex level. We investigated the benefits of identifying larvae to species using DNA to determine how often this would alter the diagnosis of resistance and whether increasing the number of larvae identified would alter the repeatability of an efficacy estimate.
Data on faecal nematode egg counts and the corresponding larval species mixes were acquired from tests conducted on commercial sheep farms. The proportion of each species present in faecal culture was determined using DNA. Efficacy was then compared for individual species and for those genera/species complexes which cannot reliably be differentiated visually. The proportion of each species present was subsequently resampled 10,000 times (repeated random sampling) and efficacy recalculated to produce the median efficacy, along with the 5 % and 95 % simulation percentiles. Subsequently, the number of larvae sampled to determine the species mix in each sample was varied from 50 to 6400 and the process repeated.
Of 152 comparisons of efficacy, 25 % of cases where genus-level identification resulted in a finding of ‘susceptible’ for that category, species-level identification returned at least one diagnosis of ‘resistant’ i.e., genus-level identification resulted in a 25 % false negative diagnosis.
When the number of larvae sampled for species identification was low (<400) variation in efficacy estimates was high, however, as sample size increased the confidence interval around the efficacy estimate decreased.
The results indicate that identifying large numbers of larvae to species using DNA has the potential to increase the accuracy and confidence in efficacy estimates achieved using the faecal egg count reduction test.
{"title":"The faecal egg count reduction test: Will identification of larvae to species improve its utility?","authors":"Dave Leathwick, Peter Green, Charlotte Bouchet, Alex Chambers, Tania Waghorn, Christian Sauermann","doi":"10.1016/j.ijpddr.2025.100589","DOIUrl":"10.1016/j.ijpddr.2025.100589","url":null,"abstract":"<div><div>In the faecal egg count reduction test, visual identification of larvae cultured from faeces enables the egg counts to be apportioned to species/genera, resulting in a more accurate test. However, morphology cannot reliably differentiate some species meaning that, in some cases, efficacy can only be estimated at the genus or species-complex level. We investigated the benefits of identifying larvae to species using DNA to determine how often this would alter the diagnosis of resistance and whether increasing the number of larvae identified would alter the repeatability of an efficacy estimate.</div><div>Data on faecal nematode egg counts and the corresponding larval species mixes were acquired from tests conducted on commercial sheep farms. The proportion of each species present in faecal culture was determined using DNA. Efficacy was then compared for individual species and for those genera/species complexes which cannot reliably be differentiated visually. The proportion of each species present was subsequently resampled 10,000 times (repeated random sampling) and efficacy recalculated to produce the median efficacy, along with the 5 % and 95 % simulation percentiles. Subsequently, the number of larvae sampled to determine the species mix in each sample was varied from 50 to 6400 and the process repeated.</div><div>Of 152 comparisons of efficacy, 25 % of cases where genus-level identification resulted in a finding of ‘susceptible’ for that category, species-level identification returned at least one diagnosis of ‘resistant’ i.e., genus-level identification resulted in a 25 % false negative diagnosis.</div><div>When the number of larvae sampled for species identification was low (<400) variation in efficacy estimates was high, however, as sample size increased the confidence interval around the efficacy estimate decreased.</div><div>The results indicate that identifying large numbers of larvae to species using DNA has the potential to increase the accuracy and confidence in efficacy estimates achieved using the faecal egg count reduction test.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"27 ","pages":"Article 100589"},"PeriodicalIF":4.1,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143726167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-20DOI: 10.1016/j.ijpddr.2025.100588
Zachary Caterer , Rachel V. Horejsi , Carly Weber , Blake Mathisen , Chase N. Nelson , Maggie Bagatta , Ireland Coughlin , Megan Wettstein , Ankit Kulshrestha , Hui Siang Benjamin Lee , Leonardo R. Nunn , Mostafa Zamanian , Nicolas J. Wheeler
Image-based phenotypic screening is a fundamental technique used to better understand the basic biology of helminths and advance discovery of new anthelmintics. Miniaturization of screening platforms and automated microscopy have led to a surge in imaging data and necessitated software to organize and analyze these data. Traditionally, these analyses are performed remotely on high-performance computers, often requiring an understanding of a command line interface (CLI) and the ability to write scripts to control the software or job scheduler. Requiring access to specialized computing equipment and advanced computational skills raises the barrier to entry for these sorts of studies. The development of efficient, performant computer and graphical processing units for personal computers and cheaper imaging solutions has made the requirement of remote servers superfluous for many small to medium-scale screens, but most analytical software still require interaction with a CLI. To democratize the analysis of image-based phenotypic screens, we have developed a graphical user interface (GUI) for wrmXpress, a tool that integrates many popular computational pipelines for analyzing imaging data of parasitic and free-living worms. The GUI operates on any personal computer using the operating system's native web browser, allowing users to configure and run analyses using a point-and-click approach. Containerization of the application eliminates the need to install specialized programming libraries and dependencies, further increasing the ease of use. GUI development required a substantial reorganization of the wrmXpress backend codebase, which allowed for the addition of a new pipeline for high-resolution tracking of worm behavior, and we demonstrate its functionality by showing that praziquantel modulates the behavior of Schistosoma mansoni miracidia. These advances make cutting-edge analyses of image-based phenotyping of worms more equitable and accessible.
{"title":"A graphical user interface for wrmXpress 2.0 streamlines helminth phenotypic screening","authors":"Zachary Caterer , Rachel V. Horejsi , Carly Weber , Blake Mathisen , Chase N. Nelson , Maggie Bagatta , Ireland Coughlin , Megan Wettstein , Ankit Kulshrestha , Hui Siang Benjamin Lee , Leonardo R. Nunn , Mostafa Zamanian , Nicolas J. Wheeler","doi":"10.1016/j.ijpddr.2025.100588","DOIUrl":"10.1016/j.ijpddr.2025.100588","url":null,"abstract":"<div><div>Image-based phenotypic screening is a fundamental technique used to better understand the basic biology of helminths and advance discovery of new anthelmintics. Miniaturization of screening platforms and automated microscopy have led to a surge in imaging data and necessitated software to organize and analyze these data. Traditionally, these analyses are performed remotely on high-performance computers, often requiring an understanding of a command line interface (CLI) and the ability to write scripts to control the software or job scheduler. Requiring access to specialized computing equipment and advanced computational skills raises the barrier to entry for these sorts of studies. The development of efficient, performant computer and graphical processing units for personal computers and cheaper imaging solutions has made the requirement of remote servers superfluous for many small to medium-scale screens, but most analytical software still require interaction with a CLI. To democratize the analysis of image-based phenotypic screens, we have developed a graphical user interface (GUI) for wrmXpress, a tool that integrates many popular computational pipelines for analyzing imaging data of parasitic and free-living worms. The GUI operates on any personal computer using the operating system's native web browser, allowing users to configure and run analyses using a point-and-click approach. Containerization of the application eliminates the need to install specialized programming libraries and dependencies, further increasing the ease of use. GUI development required a substantial reorganization of the wrmXpress backend codebase, which allowed for the addition of a new pipeline for high-resolution tracking of worm behavior, and we demonstrate its functionality by showing that praziquantel modulates the behavior of <em>Schistosoma mansoni</em> miracidia. These advances make cutting-edge analyses of image-based phenotyping of worms more equitable and accessible.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"27 ","pages":"Article 100588"},"PeriodicalIF":4.1,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143678955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-26DOI: 10.1016/j.ijpddr.2025.100587
Autumn Collins , Sierra Varley , Tobias Clark , Nathan Chubb , Sean Forrester , Jean-Paul Desaulniers
The acetylcholine-gated chloride channel (ACC) family in parasitic nematodes represents a promising target for anthelmintic drug development. Levamisole, a widely known and utilized cholinergic agonist, has been used for decades to address many types of parasitic infections by targeting nematode nicotinic acetylcholine receptors (nAChRs) in nematodes. In this study, we report the synthesis and pharmacological evaluation of eight levamisole derivatives, five of which are novel, on the H. contortus ACC-2 receptor. This includes a CF3-derivatized compound we have identified as compound 6 whose structure contains levamisole as a backbone with the addition of a 2-trifluoromethyl benzyl group. Electrophysiological assays revealed that compound 6 exhibited a five-fold increase in sensitivity (EC50 20 μM) compared to levamisole (EC50 100 μM), our parent compound, with an EC50 comparable to that of acetylcholine (20 μM). Investigation of the in silico docking of compound 6 with H. contortus ACC-2 suggest that it interacts uniquely within the H. contortus ACC-2 binding pocket, which may contribute to its increased receptor sensitivity. These findings highlight the potential of structural modifications containing an electron-withdrawing group at the 2-position which can significantly enhance activity at the H. contortus ACC-2 receptor. This opens many avenues for the development of more effective treatments against parasitic nematodes, in an environment with increasing resistance.
{"title":"Increased activity of CF3-derivatized levamisole at the ACC-2 receptor from the parasitic nematode Haemonchus contortus","authors":"Autumn Collins , Sierra Varley , Tobias Clark , Nathan Chubb , Sean Forrester , Jean-Paul Desaulniers","doi":"10.1016/j.ijpddr.2025.100587","DOIUrl":"10.1016/j.ijpddr.2025.100587","url":null,"abstract":"<div><div>The acetylcholine-gated chloride channel (ACC) family in parasitic nematodes represents a promising target for anthelmintic drug development. Levamisole, a widely known and utilized cholinergic agonist, has been used for decades to address many types of parasitic infections by targeting nematode nicotinic acetylcholine receptors (nAChRs) in nematodes. In this study, we report the synthesis and pharmacological evaluation of eight levamisole derivatives, five of which are novel, on the <em>H. contortus</em> ACC-2 receptor. This includes a CF<sub>3</sub>-derivatized compound we have identified as compound <strong>6</strong> whose structure contains levamisole as a backbone with the addition of a 2-trifluoromethyl benzyl group. Electrophysiological assays revealed that compound <strong>6</strong> exhibited a five-fold increase in sensitivity (EC<sub>50</sub> 20 μM) compared to levamisole (EC<sub>50</sub> 100 μM), our parent compound, with an EC<sub>50</sub> comparable to that of acetylcholine (20 μM). Investigation of the <em>in silico</em> docking of compound <strong>6</strong> with <em>H. contortus</em> ACC-2 suggest that it interacts uniquely within the <em>H. contortus</em> ACC-2 binding pocket, which may contribute to its increased receptor sensitivity. These findings highlight the potential of structural modifications containing an electron-withdrawing group at the 2-position which can significantly enhance activity at the <em>H. contortus</em> ACC-2 receptor. This opens many avenues for the development of more effective treatments against parasitic nematodes, in an environment with increasing resistance.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"27 ","pages":"Article 100587"},"PeriodicalIF":4.1,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-21DOI: 10.1016/j.ijpddr.2025.100586
Chun-Hsien Chen , Jian-Ming Huang , Yu-Jen Wang , Chih-Ming Tsai , Wei-Chen Lin
This review examines the advancements in antimicrobial drug discovery with in vitro assays for Acanthamoeba, highlighting the efficacy of current topical antimicrobial agents. In recent decades, the treatment and diagnosis of Acanthamoeba keratitis (AK) have presented clinical challenges. Clinicians often rely on clinical judgment, risk factors, and patient travel history to guide initial treatment decisions. The clinical presentation of AK frequently coincides with bacterial and fungal keratitis, leading to delays in diagnostic confirmation. This review compiles a list of commonly used antimicrobial agents that may be useful in controlling and preventing Acanthamoeba and other microbial infections during the diagnostic waiting period. Due to their unique life cycle, consisting of both trophozoite and cyst stages, amoebae exhibit resistance to various clinical drugs. Current research efforts are focused on identifying alternative and effective treatment options. Despite the ongoing characterization of various cytocidal agents from natural and synthetic sources, chlorhexidine gluconate (CHG) and polyhexamethylene biguanide (PHMB) have emerged as the most effective therapies for AK. Drawing from previous studies, we catalog several commonly used antimicrobial agents that may enhance the efficacy of PHMB and CHG while also preventing other microbial infections. These alternative agents present promising options for treating AK cases. This review evaluates progress in anti-amoebic drug discovery, focusing on antibiotics and cataloging their activity at different stages of Acanthamoeba.
{"title":"Recent in vitro advances in the ocular antimicrobial agents against Acanthamoeba","authors":"Chun-Hsien Chen , Jian-Ming Huang , Yu-Jen Wang , Chih-Ming Tsai , Wei-Chen Lin","doi":"10.1016/j.ijpddr.2025.100586","DOIUrl":"10.1016/j.ijpddr.2025.100586","url":null,"abstract":"<div><div>This review examines the advancements in antimicrobial drug discovery with in vitro assays for <em>Acanthamoeba</em>, highlighting the efficacy of current topical antimicrobial agents. In recent decades, the treatment and diagnosis of Acanthamoeba keratitis (AK) have presented clinical challenges. Clinicians often rely on clinical judgment, risk factors, and patient travel history to guide initial treatment decisions. The clinical presentation of AK frequently coincides with bacterial and fungal keratitis, leading to delays in diagnostic confirmation. This review compiles a list of commonly used antimicrobial agents that may be useful in controlling and preventing <em>Acanthamoeba</em> and other microbial infections during the diagnostic waiting period. Due to their unique life cycle, consisting of both trophozoite and cyst stages, amoebae exhibit resistance to various clinical drugs. Current research efforts are focused on identifying alternative and effective treatment options. Despite the ongoing characterization of various cytocidal agents from natural and synthetic sources, chlorhexidine gluconate (CHG) and polyhexamethylene biguanide (PHMB) have emerged as the most effective therapies for AK. Drawing from previous studies, we catalog several commonly used antimicrobial agents that may enhance the efficacy of PHMB and CHG while also preventing other microbial infections. These alternative agents present promising options for treating AK cases. This review evaluates progress in anti-amoebic drug discovery, focusing on antibiotics and cataloging their activity at different stages of <em>Acanthamoeba</em>.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"27 ","pages":"Article 100586"},"PeriodicalIF":4.1,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.ijpddr.2025.100585
Kateryna Starynets , Ana Paunkov , Anja Wagner , Klaus Kratochwill , Christian Klotz , David Leitsch
The microaerophilic/anaerobic protist Giardia lamblia is a world-wide occurring parasite of the human small intestine. It causes giardiasis which manifests as diarrhoea accompanied by other sequelae. Giardiasis is most commonly treated with either the 5-nitroimidazole metronidazole or the benzimidazole albendazole. Unfortunately, the number of refractory cases is increasing, which is probably caused, at least in part, by drug resistance. However, most attempts to isolate metronidazole-resistant G. lamblia strains from patients have failed so far because the parasites were not resistant when tested in vitro.
We hypothesized that this failure might be caused by drug assay conditions which are standardly anaerobic, and performed metronidazole susceptibility testing with two well studied strains, i.e. WB C6 and BRIS/87/HEPU/713 (strain 713) under microaerophilic conditions. Indeed, 713 proved to be less susceptible to metronidazole under microaerophilic conditions as compared to anaerobic conditions, and residual growth was even noted at concentrations of metronidazole similar to those in the serum of treated patients (i.e. about 100 μM). Further experiments showed that 713 also grows much faster under microaerobic conditions than WB C6. Reduced susceptibility to metronidazole under microaerobic conditions was also observed in a clinical isolate from a refractory giardiasis case.
Two-dimensional gel electrophoresis showed that microaerobic growth was accompanied by the upregulation of superoxide reductase, a pyridoxamine 5′-phosphate oxidase putative domain-containing protein, and a TlpA-like protein in 713 but not in WB C6. All three proteins are known, or can be predicted to have antioxidant functions. Indeed, overexpression of pyridoxamine 5′-phosphate oxidase in WB C6 from a plasmid carrying the respective gene behind the arginine deiminase promoter significantly improved growth of the transfected cell line under microaerobic conditions. Moreover, similarly overexpressed superoxide reductase conferred significant protection against metronidazole.
Our results suggest that oxygen concentrations can affect the outcomes of metronidazole treatment against G. lamblia.
{"title":"Culturing of Giardia lamblia under microaerobic conditions can impact metronidazole susceptibility by inducing increased expression of antioxidant enzymes","authors":"Kateryna Starynets , Ana Paunkov , Anja Wagner , Klaus Kratochwill , Christian Klotz , David Leitsch","doi":"10.1016/j.ijpddr.2025.100585","DOIUrl":"10.1016/j.ijpddr.2025.100585","url":null,"abstract":"<div><div>The microaerophilic/anaerobic protist <em>Giardia lamblia</em> is a world-wide occurring parasite of the human small intestine. It causes giardiasis which manifests as diarrhoea accompanied by other sequelae. Giardiasis is most commonly treated with either the 5-nitroimidazole metronidazole or the benzimidazole albendazole. Unfortunately, the number of refractory cases is increasing, which is probably caused, at least in part, by drug resistance. However, most attempts to isolate metronidazole-resistant <em>G</em>. <em>lamblia</em> strains from patients have failed so far because the parasites were not resistant when tested <em>in vitro</em>.</div><div>We hypothesized that this failure might be caused by drug assay conditions which are standardly anaerobic, and performed metronidazole susceptibility testing with two well studied strains, i.e. WB C6 and BRIS/87/HEPU/713 (strain 713) under microaerophilic conditions. Indeed, 713 proved to be less susceptible to metronidazole under microaerophilic conditions as compared to anaerobic conditions, and residual growth was even noted at concentrations of metronidazole similar to those in the serum of treated patients (i.e. about 100 μM). Further experiments showed that 713 also grows much faster under microaerobic conditions than WB C6. Reduced susceptibility to metronidazole under microaerobic conditions was also observed in a clinical isolate from a refractory giardiasis case.</div><div>Two-dimensional gel electrophoresis showed that microaerobic growth was accompanied by the upregulation of superoxide reductase, a pyridoxamine 5′-phosphate oxidase putative domain-containing protein, and a TlpA-like protein in 713 but not in WB C6. All three proteins are known, or can be predicted to have antioxidant functions. Indeed, overexpression of pyridoxamine 5′-phosphate oxidase in WB C6 from a plasmid carrying the respective gene behind the arginine deiminase promoter significantly improved growth of the transfected cell line under microaerobic conditions. Moreover, similarly overexpressed superoxide reductase conferred significant protection against metronidazole.</div><div>Our results suggest that oxygen concentrations can affect the outcomes of metronidazole treatment against <em>G</em>. <em>lamblia</em>.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"27 ","pages":"Article 100585"},"PeriodicalIF":4.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143179624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-31DOI: 10.1016/j.ijpddr.2025.100584
Pablo D. Jimenez Castro , Jennifer L. Willcox , Haresh Rochani , Holly L. Richmond , Heather E. Martinez , Cecilia E. Lozoya , Christian Savard , Christian M. Leutenegger
Ancylostoma caninum is the most significant intestinal nematode parasite of dogs. We acquired fecal surveillance data from a large population of dogs in the United States (US). A diagnostic test using real-time PCR (qPCR) for Ancylostoma spp. and allele-specific qPCR detecting the SNP F167Y in the isotype 1 of the Beta-tubulin gene, was used in 885,424 randomized canine fecal samples collected between March 2022 and December 2023. Overall, Ancylostoma spp. had a prevalence of 1.76% (15,537/885,424), with the highest in the South 3.73% (10,747/287,576), and the lowest in the West 0.45% (632/140,282). Within the subset of Ancylostoma spp.-detected dogs used for further analysis, the F167Y SNP had an overall prevalence of 14.44% with the highest in the West and the lowest in the Midwest (10.76%). The greyhound exhibited a higher prevalence of Ancylostoma spp. infections (17.03%) and a higher prevalence of the F167Y polymorphism (33.6%) compared to non-greyhounds (13.7% and 2.08%), respectively, but were not associated with the highest risk for the F167Y polymorphism. Sex did not influence hookworm infection nor F167Y polymorphism prevalence. Intact dogs had a prevalence of hookworm infection and F167Y polymorphism of 3.88% and 15.66%, respectively. Puppies showed increased prevalence of hookworms (3.70%) and the F167Y SNP (17.1%). Greyhounds, bluetick coonhounds, and boerboels had the highest relative risks for hookworm infection, while Cavalier King Charles spaniels, Havanese, and shiba inus had the lowest. The top and bottom three with the highest and lowest RR for the F167Y SNP were the old English sheepdog, American foxhound, and toy poodle Toy, and shih tzu, Maltese, and Australian cattle dogs, respectively. This study highlights the value of an accessible diagnostic qPCR test with fast turnaround in unraveling the molecular epidemiology of hookworms and benzimidazole resistance, as well as explore potentially important risk factorsin dogs with routine veterinary care.
{"title":"Investigation of risk factors associated with Ancylostoma spp. infection and the benzimidazole F167Y resistance marker polymorphism in dogs from the United States","authors":"Pablo D. Jimenez Castro , Jennifer L. Willcox , Haresh Rochani , Holly L. Richmond , Heather E. Martinez , Cecilia E. Lozoya , Christian Savard , Christian M. Leutenegger","doi":"10.1016/j.ijpddr.2025.100584","DOIUrl":"10.1016/j.ijpddr.2025.100584","url":null,"abstract":"<div><div><em>Ancylostoma caninum</em> is the most significant intestinal nematode parasite of dogs. We acquired fecal surveillance data from a large population of dogs in the United States (US). A diagnostic test using real-time PCR (qPCR) for <em>Ancylostoma</em> spp. and allele-specific qPCR detecting the SNP F167Y in the isotype 1 of the Beta-tubulin gene, was used in 885,424 randomized canine fecal samples collected between March 2022 and December 2023. Overall, <em>Ancylostoma</em> spp. had a prevalence of 1.76% (15,537/885,424), with the highest in the South 3.73% (10,747/287,576), and the lowest in the West 0.45% (632/140,282). Within the subset of <em>Ancylostoma</em> spp<em>.-</em>detected dogs used for further analysis, the F167Y SNP had an overall prevalence of 14.44% with the highest in the West and the lowest in the Midwest (10.76%). The greyhound exhibited a higher prevalence of <em>Ancylostoma</em> spp. infections (17.03%) and a higher prevalence of the F167Y polymorphism (33.6%) compared to non-greyhounds (13.7% and 2.08%), respectively, but were not associated with the highest risk for the F167Y polymorphism. Sex did not influence hookworm infection nor F167Y polymorphism prevalence. Intact dogs had a prevalence of hookworm infection and F167Y polymorphism of 3.88% and 15.66%, respectively. Puppies showed increased prevalence of hookworms (3.70%) and the F167Y SNP (17.1%). Greyhounds, bluetick coonhounds, and boerboels had the highest relative risks for hookworm infection, while Cavalier King Charles spaniels, Havanese, and shiba inus had the lowest. The top and bottom three with the highest and lowest RR for the F167Y SNP were the old English sheepdog, American foxhound, and toy poodle Toy, and shih tzu, Maltese, and Australian cattle dogs, respectively. This study highlights the value of an accessible diagnostic qPCR test with fast turnaround in unraveling the molecular epidemiology of hookworms and benzimidazole resistance, as well as explore potentially important risk factorsin dogs with routine veterinary care.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"27 ","pages":"Article 100584"},"PeriodicalIF":4.1,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143222955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-22DOI: 10.1016/j.ijpddr.2025.100582
Lucia Borrallo-Lopez , Laura Guzman , Noelia G. Romero , Anna Sampietro , Ana Mallo-Abreu , Laia Guardia-Escote , Elisabet Teixidó , Burkhard Flick , Xavier Fernàndez-Busquets , Diego Muñoz-Torrero , Marta Barenys
Background
Malaria during pregnancy implies a high risk for the mother and the developing child. However, the therapeutic options for pregnant women have historically been very limited, especially during the first trimester of pregnancy due to potential adverse effects on embryo-fetal development. Recently, there has been great controversy regarding these potential embryo-fetal adverse effects because the results of rodent studies were not in accordance with the clinical data available, and finally the WHO has changed the recommendations for pregnant women with uncomplicated P. falciparum malaria to treatment with artemether-lumefantrine during the first trimester. The discrepancy between pre-clinical and clinical studies has been attributed to species-differences in the duration of the window of susceptibility of circulating primitive erythroblasts.
Methods
Here we provide a tool based on an alternative method to animal experimentation that accelerates the research of novel drugs for pregnant women. We have adapted the zebrafish embryo developmental toxicity assay to include hemoglobin staining in the embryos and two time-points of lethality and dysmorphogenesis evaluation. These two time-points were selected to include one when the development is independent of and one when the development is dependent of erythrocytes function. The method was used to test four marketed antimalarial drugs and three new antimalarial drug candidates.
Results
Our combination of tests can correctly predict the teratogenic and non-teratogenic effects of several antimalarial marketed drugs (artemisinin, quinine, chloroquine, and dihydroartemisinin + desbutyl-lumefantrine). Furthermore, we have tested three new drug candidates (GS-GUAN, DONE3TCl, and YAT2150) with novel mechanisms of action, and different from those of the marketed antimalarial drugs.
Conclusions
We propose a decision tree combining the results of the two time-points of evaluation together with the information on significant erythrocyte depletion. The aim of this decision tree is to identify compounds with no or lower hazard on teratogenicity or erythrocyte depletion at an early phase of the drug development process.
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Pub Date : 2025-01-22DOI: 10.1016/j.ijpddr.2025.100583
Giulia Rigamonti , Fabrizia Veronesi , Elisabetta Chiaradia , Petra Gosten-Heinrich , Antonia Müller , Leonardo Brustenga , Stefano de Angelis , Alessia Tognoloni , Riccardo De Santo , Christian Klotz , Marco Lalle
Giardia duodenalis is a widespread intestinal protozoan that affects mammals, including humans. Symptoms can range from being subclinical to causing severe abdominal pain and diarrhoea. Giardiasis often requires repeated treatment with synthetic drugs like metronidazole. In recent years, treatment failures in clinical cases involving nitroimidazoles have been increasingly reported. Consequently, identifying therapeutic alternatives is necessary. Medicinal plants have traditionally been used as antiparasitic compounds, but systematic evaluation under controlled experimental conditions is often lacking. Here, we evaluated the in vitro efficacy of Tabebuia avellanedae dry and hydroalcoholic extracts, as well as one of its active compounds, β-lapachone, as potential treatment against G. duodenalis infection. We observed effective antigiardial activity for all tested compounds, with β-lapachone exhibiting lower IC50 values than metronidazole. Cytotoxic effects often limit therapeutic concentration windows of opportunity, and choosing an informative model to assess them is not straightforward. In the present case, only T. avellanedae hydroalcoholic extract showed no cytotoxicity on tumoral human intestinal Caco-2 cell line, and only a trend of inhibition when tested on canine epithelial kidney MDCK cells. To introduce a more physiological test system, we used in vitro G. duodenalis infection experiments in a trans-well set-up using organoid derived monolayers (ODM) to assess at the same time drug efficacy against the parasite and safety on primary human intestinal epithelia, a likely surrogate for in vivo conditions. Our studies using this model point towards the potential therapeutic opportunity for non-systemic applications of T. avellanedae extracts and a relevant ingredient of these, β-lapachone. The data suggest that ODM co-cultures with G. duodenalis are suitable for testing antigiardial compounds, providing a more informative in vitro model before progressing to in vivo tests.
{"title":"Selective activity of Tabebuia avellanedae against Giardia duodenalis infecting organoid-derived human gastrointestinal epithelia","authors":"Giulia Rigamonti , Fabrizia Veronesi , Elisabetta Chiaradia , Petra Gosten-Heinrich , Antonia Müller , Leonardo Brustenga , Stefano de Angelis , Alessia Tognoloni , Riccardo De Santo , Christian Klotz , Marco Lalle","doi":"10.1016/j.ijpddr.2025.100583","DOIUrl":"10.1016/j.ijpddr.2025.100583","url":null,"abstract":"<div><div><em>Giardia duodenalis</em> is a widespread intestinal protozoan that affects mammals, including humans. Symptoms can range from being subclinical to causing severe abdominal pain and diarrhoea. Giardiasis often requires repeated treatment with synthetic drugs like metronidazole. In recent years, treatment failures in clinical cases involving nitroimidazoles have been increasingly reported. Consequently, identifying therapeutic alternatives is necessary. Medicinal plants have traditionally been used as antiparasitic compounds, but systematic evaluation under controlled experimental conditions is often lacking. Here, we evaluated the <em>in vitro</em> efficacy of <em>Tabebuia avellanedae</em> dry and hydroalcoholic extracts, as well as one of its active compounds, β-lapachone, as potential treatment against <em>G. duodenalis</em> infection. We observed effective antigiardial activity for all tested compounds, with β-lapachone exhibiting lower IC<sub>50</sub> values than metronidazole. Cytotoxic effects often limit therapeutic concentration windows of opportunity, and choosing an informative model to assess them is not straightforward. In the present case, only <em>T. avellanedae</em> hydroalcoholic extract showed no cytotoxicity on tumoral human intestinal Caco-2 cell line, and only a trend of inhibition when tested on canine epithelial kidney MDCK cells. To introduce a more physiological test system, we used <em>in vitro G. duodenalis</em> infection experiments in a trans-well set-up using organoid derived monolayers (ODM) to assess at the same time drug efficacy against the parasite and safety on primary human intestinal epithelia, a likely surrogate for <em>in vivo</em> conditions. Our studies using this model point towards the potential therapeutic opportunity for non-systemic applications of <em>T. avellanedae</em> extracts and a relevant ingredient of these, β-lapachone. The data suggest that ODM co-cultures with <em>G. duodenalis</em> are suitable for testing antigiardial compounds, providing a more informative <em>in vitro</em> model before progressing to <em>in vivo</em> tests.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"27 ","pages":"Article 100583"},"PeriodicalIF":4.1,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143046545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-18DOI: 10.1016/j.ijpddr.2025.100581
Marc Kaethner , Pascal Zumstein , Joachim Müller , Matías Preza , Philipp Grossenbacher , Anissa Bartetzko , Laura Vetter , Martin Lochner , Stefan Schürch , Clement Regnault , Daniel Villalobos Ramírez , Britta Lundström-Stadelmann
Alveolar echinococcosis (AE) is a severe zoonotic disease caused by the metacestode stage of the fox tapeworm Echinococcus multilocularis. We recently showed that E. multilocularis metacestode vesicles scavenge large amounts of L-threonine from the culture medium. This motivated us to study the effect of L-threonine on the parasite and how it is metabolized. We established a novel metacestode vesicle growth assay with an automated readout, which showed that L-threonine treatment led to significantly increased parasite growth. In addition, L-threonine increased the formation of novel metacestode vesicles from primary parasite cell cultures in contrast to the non-proteinogenic threonine analog 3-hydroxynorvaline. Tracing of [U-13C]-L-threonine and metabolites in metacestode vesicles and culture medium resulted in the detection of [U-13C]-labeling in aminoacetone and glycine, indicating that L-threonine was metabolized by threonine dehydrogenase (TDH). EmTDH-mediated threonine metabolism in the E. multilocularis metacestode stage was further confirmed by quantitative real-time PCR, which demonstrated high expression of emtdh in in vitro cultured metacestode vesicles and also in metacestode samples obtained from infected animals. EmTDH was enzymatically active in metacestode vesicle extracts. The compounds disulfiram, myricetin, quercetin, sanguinarine, and seven quinazoline carboxamides were evaluated for their ability to inhibit recombinantly expressed EmTDH. The most potent inhibitors, albeit not very strong or highly specific, were disulfiram, myricetin and sanguinarine. These compounds were subsequently tested for activity against E. multilocularis metacestode vesicles and primary parasite cells and only sanguinarine demonstrated significant in vitro activity. However, TDH is not its only cellular target, and it is also known to be highly toxic. Our findings suggest that additional targets of sanguinarine should be explored, and that it may serve as a foundation for developing more specific compounds against the parasite. Moreover, the EmTDH assay could be a valuable high-throughput, target-based platform for discovering novel anti-echinococcal compounds.
{"title":"Investigation of the threonine metabolism of Echinococcus multilocularis: The threonine dehydrogenase as a potential drug target in alveolar echinococcosis","authors":"Marc Kaethner , Pascal Zumstein , Joachim Müller , Matías Preza , Philipp Grossenbacher , Anissa Bartetzko , Laura Vetter , Martin Lochner , Stefan Schürch , Clement Regnault , Daniel Villalobos Ramírez , Britta Lundström-Stadelmann","doi":"10.1016/j.ijpddr.2025.100581","DOIUrl":"10.1016/j.ijpddr.2025.100581","url":null,"abstract":"<div><div>Alveolar echinococcosis (AE) is a severe zoonotic disease caused by the metacestode stage of the fox tapeworm <em>Echinococcus multilocularis</em>. We recently showed that <em>E. multilocularis</em> metacestode vesicles scavenge large amounts of L-threonine from the culture medium. This motivated us to study the effect of L-threonine on the parasite and how it is metabolized. We established a novel metacestode vesicle growth assay with an automated readout, which showed that L-threonine treatment led to significantly increased parasite growth. In addition, L-threonine increased the formation of novel metacestode vesicles from primary parasite cell cultures in contrast to the non-proteinogenic threonine analog 3-hydroxynorvaline. Tracing of [U-<sup>13</sup>C]-L-threonine and metabolites in metacestode vesicles and culture medium resulted in the detection of [U-<sup>13</sup>C]-labeling in aminoacetone and glycine, indicating that L-threonine was metabolized by threonine dehydrogenase (TDH). EmTDH-mediated threonine metabolism in the <em>E. multilocularis</em> metacestode stage was further confirmed by quantitative real-time PCR, which demonstrated high expression of <em>emtdh</em> in <em>in vitro</em> cultured metacestode vesicles and also in metacestode samples obtained from infected animals. EmTDH was enzymatically active in metacestode vesicle extracts. The compounds disulfiram, myricetin, quercetin, sanguinarine, and seven quinazoline carboxamides were evaluated for their ability to inhibit recombinantly expressed EmTDH. The most potent inhibitors, albeit not very strong or highly specific, were disulfiram, myricetin and sanguinarine. These compounds were subsequently tested for activity against <em>E. multilocularis</em> metacestode vesicles and primary parasite cells and only sanguinarine demonstrated significant <em>in vitro</em> activity. However, TDH is not its only cellular target, and it is also known to be highly toxic. Our findings suggest that additional targets of sanguinarine should be explored, and that it may serve as a foundation for developing more specific compounds against the parasite. Moreover, the EmTDH assay could be a valuable high-throughput, target-based platform for discovering novel anti-echinococcal compounds.</div></div>","PeriodicalId":13775,"journal":{"name":"International Journal for Parasitology: Drugs and Drug Resistance","volume":"27 ","pages":"Article 100581"},"PeriodicalIF":4.1,"publicationDate":"2025-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143028707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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